Post Malone proposed to Christy Lee with a massive engagement ring that could be worth up to $2.5 million.

The announcement was made via Lee’s friend, Marina Hollyer, as she posted a photo of the couple hugging one another, as Lee showed off her new piece of jewelry, a veil and a “Bride to Be” sash. In snaps shared by various friends to Instagram, the country singer, 31, and his bride-to-be embraced as Lee shows off her new sparkler, which appears to be a large oval-shaped diamond. Experts estimate that the ring could contain up to 25 carats and be worth up to $2.5 million. Olivia Landau, founder of The Clear Cut, now part of Blue Nile, weighed in on the diamond’s potential specs in a statement shared with PEOPLE.

Landau notes that the bold diamond paired with an understated setting is in line with celebrity ring trends, like Madison Beer’s elongated cushion-cut ring and Kylie Jenner’s pear-shaped pinky ring. Ali Galgano, founder of New York and Greenwich-based fine jewelry house Serpentine Jewels, thinks the ring contains between 15 and 20 carats and worth between $1 and $2.5 million. She tells PEOPLE that the design feels like an homage to celebrity rings of the early 2000s.